The state health department has confirmed the presence of polychlorinated biphenyls (PCBs), an organic chemical contaminant, in a reservoir tank of a water system that serves a population of about 5,800 on the west side of Kauai.

The department determined drinking water served to the public from the Kekaha-Waimea Drinking Water System was safe because samples collected from the water distribution system just after the Paua Valley Tank did not contain PCBs. The Kauai Department of Water, however, took the tank out of service as a precautionary measure.

In September, samples collected at the tank as part of a maintenance project indicated that PCBs might be present in an oily sheen layer skimmed from the surface of the water. In an October sample, the health department learned scrapings from the interior coating of the tank wall were confirmed to contain PCBs as well.

The health department will work closely with the Kauai Department of Water to ensure that adequate steps are taken to remove the source of PCBs and thorough water quality testing is conducted before the tank is placed back into service.

To date, the health department says the Kekaha-Waimea Water System continues to be in compliance with all federal and state standards for drinking water.